【Arduino】物联网-栗子1

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gx_143 2023-05-05 16:18:55 博主文章分类：Arduino

文章标签 #include json 开发板 文章分类 Python 后端开发

使用MQTT先要有一个MQTT服务器，具体如何搭建可以看上一篇文章

这一篇主要讲下NodeMCU的使用，以及MQTT介绍和如何接发消息

NodeMCU

1. ESP8266介绍

介绍NodeMCU前需要先了解ESP8266，它是一个完整自称体系的WiFi网络解决方案，能独立运行也可为从部件连接单片机运行

具有以下特点：

超小尺寸
低功耗
内置TCP/IP协议
可编程
低成本

2. NodeMCU介绍

NodeMCU是一款基于ESP8266模块的开源硬件，符合Arduino框架。同时可使用Node.js编程

【Arduino】物联网-栗子1_json

NodeMCU引脚：

【Arduino】物联网-栗子1_#include_02

3. WiFi测试

先要安装Arduino IDE For ESP8266
Arduino IDE For ESP8266是根据Arduino修改的专门烧写ESP8266开发板的IDE。在装好Arduino IDE后：

打开Arduino 文件->首选项，在附加开发管理网站中填入http://arduino.esp8266.com/stable/package_esp8266com_index.json，然后点击确定保存

【Arduino】物联网-栗子1_#include_03

重启IDE后，打开工具->开发板->开发板管理器；搜索ESP8266，选择esp 8266 by ESP8266 Community安装

【Arduino】物联网-栗子1_开发板_04

下载完成后可以在开发板选项中看到ESP8266 Module,以及NodeMCU等可选开发板

将NodeMCU通过usb连接到电脑，在工具下选择相应配置

【Arduino】物联网-栗子1_json_05

波特率越大烧录程序速度越快但有可能出错
端口选择NodeMCU对应端口，如果没看到端口，那是驱动没有装，装驱动可以看这里

http://www.arduino.cn/thread-1008-1-1.html

打开示例选择ESP8266WiFi中的WiFiScan

【Arduino】物联网-栗子1_json_06

烧到板子上打开窗口监视器可以看到扫描出来的附近热点

【Arduino】物联网-栗子1_开发板_07

MQTT

1. MQTT介绍

消息队列遥测传输(MQTT)是IBM开发的即时通讯协议，为计算能力有限且工作在低带宽、不可靠网络的传感器或控制设备而设计。比如对于移动开发，它可以用于消息推送，即时通讯等等

特性：

发布/订阅的消息模式，提供一对多的消息发布
使用TCP/IP提供网络连接
有三种消息发布服务质量，至多一次，至少一次，只有一次
传输小、开销小
LastWill通知中断机制

2. MQTT原理介绍

客户端：发布者(Publish)、订阅者(SubScribe)，客户端有ID,ID冲突会挤掉先连接客户端。
服务器端：代理(Broker)
消息：主题(Topic)+负载(payload)

【Arduino】物联网-栗子1_开发板_08

举个场景为例：

【Arduino】物联网-栗子1_#include_09

QQ用户2(账号QQ1000)向QQ用户1(QQ9999)发送消息“Hello World”.
发送者：QQ用户2
订阅者：QQ用户1
消息：QQ9999+”Hello World”.

消息发送至服务器，服务器查找QQ9999对应的用户后，发送信息给QQ用户2.

3. MQTT ESP8266库

菜单“项目”-“加载库”-“管理库”，搜索安装“PubSubClient”

【Arduino】物联网-栗子1_开发板_10

PubSubClient有一些示例可以打开mqtt_esp8266看下

4. MQTT接发消息体验

这里做两个示例
1. NodeMCU接受消息：服务器来控制LED灯状态

#include <ESP8266WiFi.h>
#include <PubSubClient.h>

// Update these with values suitable for your network.

const char* ssid = "******";
const char* password = "******";
const char* mqtt_server = "******";

WiFiClient espClient;
PubSubClient client(espClient);
long lastMsg = 0;
char msg[50];
int value = 0;
int LED = 5;     // LED引脚
void setup() {
  pinMode(LED, OUTPUT);     // Initialize the  pin as an output
  Serial.begin(115200);
  setup_wifi();
  client.setServer(mqtt_server, 1883);
  client.setCallback(callback);
}

void setup_wifi() {

  delay(10);
  // We start by connecting to a WiFi network
  Serial.println();
  Serial.print("Connecting to ");
  Serial.println(ssid);

  WiFi.begin(ssid, password);

  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }

  Serial.println("");
  Serial.println("WiFi connected");
  Serial.println("IP address: ");
  Serial.println(WiFi.localIP());
}

void callback(char* topic, byte* payload, unsigned int length) {
  Serial.print("Message arrived [");
  Serial.print(topic);
  Serial.print("] ");
  for (int i = 0; i < length; i++) {
    Serial.print((char)payload[i]);
  }
  Serial.println();

  // Switch on the LED if an 1 was received as first character
  if ((char)payload[0] == '1') {
    digitalWrite(LED, LOW);   // Turn the LED on (Note that LOW is the voltage level
    // but actually the LED is on; this is because
    // it is acive low on the ESP-01)
  } else {
    digitalWrite(LED, HIGH);  // Turn the LED off by making the voltage HIGH
  }

}

void reconnect() {
  // Loop until we're reconnected
  while (!client.connected()) {
    Serial.print("Attempting MQTT connection...");
    // Attempt to connect
    if (client.connect("ESP8266Client")) {
      Serial.println("connected");
      // Once connected, publish an announcement...
      client.publish("outTopic", "hello world");
      // ... and resubscribe
      client.subscribe("inTopic");
    } else {
      Serial.print("failed, rc=");
      Serial.print(client.state());
      Serial.println(" try again in 5 seconds");
      // Wait 5 seconds before retrying
      delay(5000);
    }
  }
}
void loop() {

  if (!client.connected()) {
    reconnect();
  }
  client.loop();

  long now = millis();
  if (now - lastMsg > 2000) {
    lastMsg = now;
    ++value;
    snprintf (msg, 75, "hello world #%ld", value);
    Serial.print("Publish message: ");
    Serial.println(msg);
    client.publish("outTopic", msg);
  }
}

2. NodeMCU发送消息：向服务器上传温度湿度信息

#include <ESP8266WiFi.h>
#include <PubSubClient.h>
#include <SimpleDHT.h>

WiFiClient espClient;
PubSubClient client(espClient);

int pinDHT11 = 5;
SimpleDHT11 dht11(pinDHT11);


const char* ssid = "1705";
const char* password = "Zoor170302";
const char* mqtt_server = "*****";


long lastMsg = 0;
char msg[50];
int value = 0;
int LedStatus = 4;
int LedOutPut = 14;

void setup() {
  pinMode(LedStatus, OUTPUT);
  pinMode(LedOutPut, OUTPUT);
  Serial.begin(115200);

  setup_wifi();

  client.setServer(mqtt_server, 1883);
  client.setCallback(callback);
}
// 连接wifi
void setup_wifi() {
  delay(10);
  WiFi.begin(ssid, password);

  while (WiFi.status() != WL_CONNECTED) {
    digitalWrite(LedStatus, HIGH);
    delay(500);
    digitalWrite(LedStatus, LOW);
    Serial.print(".");
  }

  Serial.println(WiFi.localIP());
}

// 订阅信息
void callback(char* topic, byte* payload, unsigned int length) {
  Serial.print("Message arrived [");
  Serial.print(topic);
  Serial.print("] ");
  for (int i = 0; i < length; i++) {
    Serial.print((char)payload[i]);
  }
  Serial.println();

  //  // Switch on the LED if an 1 was received as first character
  //  if ((char)payload[0] == '1') {
  //    digitalWrite(LED, LOW);   // Turn the LED on (Note that LOW is the voltage level
  //    // but actually the LED is on; this is because
  //    // it is acive low on the ESP-01)
  //  } else {
  //    digitalWrite(LED, HIGH);  // Turn the LED off by making the voltage HIGH
  //  }

}

void reconnect() {
  while (!client.connected()) {
    if (client.connect("ESP8266Client")) {
      client.subscribe("inTopic");
      digitalWrite(LedStatus, HIGH);
    } else {
      Serial.println("mqtt failed");
      digitalWrite(LedStatus, HIGH);
      delay(5000);
      digitalWrite(LedStatus, LOW);
    }
  }
}
void loop() {
  if (!client.connected()) {
    reconnect();
  }
  client.loop();

  long now = millis();
  if (now - lastMsg > 10000) {
    lastMsg = now;

    byte temperature = 0;
    byte humidity = 0;
    int err = SimpleDHTErrSuccess;

    if ((err = dht11.read(&temperature, &humidity, NULL)) != SimpleDHTErrSuccess) {
      delay(1000);
      return;
    }

    float tep = formatFloat((float)temperature);
    float hum = formatFloat((float)humidity);

    snprintf(msg, 75, "{Tep: %ld,Hum: %ld}", temperature, humidity);

    client.publish("outputDHT11", msg);
    Serial.println(msg);
    digitalWrite(LedOutPut, HIGH);
    delay(50);
    digitalWrite(LedOutPut, LOW);
  }
}

float formatFloat(float f)
{
  int temp = (f * 100);
  return float(temp / 100);
}

3、向阿里云Iot平台上传数据

#include <ESP8266WiFi.h>
#include <PubSubClient.h>
#include <SimpleDHT.h>
 
WiFiClient espClient;
PubSubClient client(espClient);
 
int pinDHT11 = 5;
SimpleDHT11 dht11(pinDHT11);
 
const char* ssid = "1705";
const char* password = "Zoor170302";

const char* mqtt_server = "a1PifWnko4O.iot-as-mqtt.cn-shanghai.aliyuncs.com";
const char* mqtt_username = "vCgnBR7ax2AQIFFjo8mf&a1PifWnko4O";
const char* mqtt_password = "******";
const char* mqtt_clientId = "FESA234FBDS24|securemode=3,signmethod=hmacsha1,timestamp=789|";

const char* body = "{\"id\":\"123\",\"version\":\"1.0\",\"method\":\"thing.event.property.post\",\"params\":%s}"
const char* inTopic = "/sys/a1PifWnko4O/vCgnBR7ax2AQIFFjo8mf/thing/service/property/set";

#define ALINK_BODY_FORMAT         "{\"id\":\"123\",\"version\":\"1.0\",\"method\":\"thing.event.property.post\",\"params\":%s}"
#define ALINK_TOPIC_PROP_POST     "/sys/a1PifWnko4O/vCgnBR7ax2AQIFFjo8mf/thing/event/property/post"
 
long lastMsg = 0;
char msg[50];
int value = 0;
int LedStatus = 4;
int LedOutPut = 14;
 
void setup() {
  pinMode(LedStatus, OUTPUT);
  pinMode(LedOutPut, OUTPUT);
  Serial.begin(115200);
 
  setup_wifi();
 
  client.setServer(mqtt_server, 1883);
  client.setCallback(callback);
}
// 连接wifi
void setup_wifi() {
  delay(10);
  WiFi.begin(ssid, password);
 
  while (WiFi.status() != WL_CONNECTED) {
    digitalWrite(LedStatus, HIGH);
    delay(500);
    digitalWrite(LedStatus, LOW);
    Serial.print(".");
  }
 
  Serial.println(WiFi.localIP());
}
 
// 订阅信息
void callback(char* topic, byte* payload, unsigned int length) {
  Serial.print("Message arrived [");
  Serial.print(topic);
  Serial.print("] ");
  for (int i = 0; i < length; i++) {
    Serial.print((char)payload[i]);
  }
  Serial.println();
 
  //  // Switch on the LED if an 1 was received as first character
  //  if ((char)payload[0] == '1') {
  //    digitalWrite(LED, LOW);   // Turn the LED on (Note that LOW is the voltage level
  //    // but actually the LED is on; this is because
  //    // it is acive low on the ESP-01)
  //  } else {
  //    digitalWrite(LED, HIGH);  // Turn the LED off by making the voltage HIGH
  //  }
 
}
 
void reconnect() {
  while (!client.connected()) {
    if (client.connect(mqtt_clientId,mqtt_username , mqtt_password)) {
      // client.subscribe("inTopic");
      digitalWrite(LedStatus, HIGH);
    } else {
      Serial.println("mqtt failed");
      digitalWrite(LedStatus, HIGH);
      delay(5000);
      digitalWrite(LedStatus, LOW);
    }
  }
}
void loop() {
  if (!client.connected()) {
    reconnect();
  }
  client.loop();
 
  long now = millis();
  if (now - lastMsg > 10000) {
    lastMsg = now;
 
    byte temperature = 0;
    byte humidity = 0;
    int err = SimpleDHTErrSuccess;
 
    if ((err = dht11.read(&temperature, &humidity, NULL)) != SimpleDHTErrSuccess) {
      delay(1000);
      return;
    }
 
    char param[32];
    char jsonBuf[128];

    sprintf(param, "{\"CurrentTemperature\":%d},\"RelativeHumidity:%d\"",temperature,humidity);
    sprintf(jsonBuf, ALINK_BODY_FORMAT, param);
    Serial.println(jsonBuf);
    boolean d = client.publish(ALINK_TOPIC_PROP_POST, jsonBuf);
    Serial.print("publish:0 失败;1成功");
    Serial.println(d);

    digitalWrite(LedOutPut, HIGH);
    delay(50);
    digitalWrite(LedOutPut, LOW);
  }
}
 
float formatFloat(float f)
{
  int temp = (f * 100);
  return float(temp / 100);
}

阿里云栗子：

https://help.aliyun.com/document_detail/104070.html?spm=a2c4g.11186623.6.773.5d2578dc2DCPeE